Mementos

Mementos is an achievement in GRIS. Upon unlocking the achievement, there will be an extra hidden scene that couldn't be unlocked in any other way.

Appearance
It appears to be a series of circles of different sizes with the same size.

Achieving
The player can get this achievement by getting a total of 28 mementos from all of the 5 chapters. The player can find out how to get all of the mementos in each chapter here:
 * Chapter 1
 * Chapter 2
 * Chapter 3
 * Chapter 4
 * Chapter 5